24.zote

include!("stdlib");
include!("aoc.zote");

input := read("input") >> trim;
lines := input >> split("\n");

low := 200000000000000;
high := 400000000000000;

hail := lines >> map(\>> split("@") >> map(ints));

fn check(((x1, y1, z1), (dx1, dy1, dz1)), ((x2, y2, z2), (dx2, dy2, dz2))) -> {
	// Rush to get pen and paper. Time to break out the old lin alg knowledge.

	div := dx1 * dy2 - dx2 * dy1;
    if div == 0 return false;

    t1 := (dx2 * y1 - dx2 * y2 - dy2 * x1 + dy2 * x2) / float(div);
    t2 := (dx1 * y1 - dx1 * y2 - dy1 * x1 + dy1 * x2) / float(div);

	// Cant int neg time
	if t1 < 0 or t2 < 0 return false;

	// inside?
	x := x1 + dx1*t1;
	y := y1 + dy1*t1;	

	x >= low and x <= high and y >= low and y <= high 
}

int := 0;
for (i1, (p1, d1)) in hail >> enumerate for (i2, (p2, d2)) in hail >> enumerate if i2 > i1 {
	if check([p1, d1], [p2, d2]) int += 1;
}

print(int);